Diaphragm and hydraulically-operated valve using same

ABSTRACT

The present invention relates to fluid control valves. The invention provides an improved diaphragm useful for a large hydraulically-operated valve or pressure regulating valve of the type used in pipelines to transport water, oil, gas, acids, alkalis and other fluids. The diaphragm being provided with an upper face arranged to be exposed to a control hydraulic pressure and a lower face arranged to selectively seal and open a passage between a valve inlet and a valve outlet, ribs on said upper face urging the diaphragm towards a sealing position. The diaphragm being characterized by the addition of an elastomer ring element disposed adjacent to the upper face and adjacent to the largest diameter of the diaphragm exposed inside a valve to which it may be assembled, an upper face of the flexible ring element being in pressure contact with a portion of the rigid body of the valve. The flexible ring element further urging the diaphragm towards its lower position and allowing closure of the valve without use of a metallic compression spring.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.10/884,001, filed Jul. 6, 2004 which claims priority from Israel PatentApplication, 156797, filed Jul. 6, 2003, the disclosures of both ofwhich are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to fluid control valves.

More particularly, the invention provides an improved diaphragm usefulfor a large hydraulically-operated valve or pressure regulating valve ofthe type used in pipelines to transport water, oil, gas, acids, alkalisand other fluids.

Although valves can be installed and operated in any position, in thepresent specification the term lower refers to the side of the diaphragmalways in contact with the fluid being transported. Upper refers to theopposite side of the diaphragm which may be in contact with a fluid tocontrol opening/closing of the valve.

Small fluid control valves are easily actuated by hand, foot, machine,solenoid or pilot air. Large valves, about 8″ or more, are moredifficult to operate, particularly when the fluid being transported isat high pressure, because the forces needed to prevent flow increase asthe square of the pipeline diameter. A well known solution to theproblem is to use the fluid being transported as an actuator, to form ahydraulically-operated diaphragm valve. A diaphragm valve has theadvantage of not requiring a stuffing box, and operating leak-free forthe life of the diaphragm.

Typically the diaphragm valve is operated by directing hydraulicpressure into/out of a chamber on the upper side of the diaphragm. Insome designs a steel compression spring is used in the upper chamber toensure closure of the valve when needed. When the valve is to be opened,pressure in the upper chamber is reduced and the fluid being handledpushes open the diaphragm for the resumption of flow.

Clearly it is highly desirable that the valve diaphragm operates for thelargest possible number of cycles and the longest possible time period.The cost of a failed diaphragm goes far beyond the cost of areplacement, as leakage needs to be controlled, a technician needs to besent to the site and the pipeline may need to be shut down duringreplacement of the failed component.

Hydraulically-operated diaphragm valves are known and in use.

Newberg discloses a diaphragm valve in International Publication WO02/066876 A1. The valve is operated by manually turning a controlcylinder which operates a screw mechanism to raise or lower a sealingelement extending from a diaphragm. Valves of this type are appropriateonly for small diameter conduits, as the valve is hand, nothydraulically operated.

Some designs, for example the Elastomeric Element Valve disclosed byWalton et al. in U.S. Pat. No. 6,102,071, employ a metal coilcompression spring to assist in valve closure. Such spring wasconsidered necessary in a hydraulically-operated valve because when boththe upper chamber and the passages leading to/from the pipeline are atthe same pressure, there is no substantial force available to close(Cower) the diaphragm. The problem with this design is that at smallpressure differences and low flow rates the metallic spring causesvibrations which quickly damage the diaphragm, thus making the valveinoperable. A further drawback of the design is the pressure drop causedby the spring in the pipeline during normal open-valve operation. Yet afurther problem is that after such valve has been left open for anextended period, the valve is very difficult to close, due to loss ofelasticity in the elastomer at the sharp bend proximate to the maximumoperating diameter of the diaphragm.

In response to these difficulties the present inventor developed a newdesign first disclosed 30.04.1993 in Israel Patent No. 119,963. Thedistinctive feature of this design is the presence above its concavesurface of radial and circular ribs urging the diaphragm into its closed(lower) position without requiring a steel coil compression spring forthis purpose. This design proved to be effective for smaller valves, inthe range 1/2″ to 8″ (13-203 mm). However valves larger than 8″ requiredribs on the concave surface which were wide and high. Furthermore thestrong closing force generated by these ribs produced an unacceptablepressure loss in the pipeline wherein the valve was installed.

The difficulties experienced with the diaphragm described in IsraelPatent No. 119,963 were overcome by the Spring Diaphragm for Shut-OffValves and Regulators disclosed by the present inventor in U.S. Pat. No.6,095,484. A two-part diaphragm has an upper and a spaced-apart lowertier. The lower tier functions as a conventional diaphragm. The uppertier forms a resilient disk urging the lower part towards its closed(lower) position. Both parts are provided with ribs. This design wastested and found to meet all operational and reliability requirements.However, manufacturing cost was too high in view of the sharpcompetition existing in the field of hydraulic valves.

OBJECTS OF THE INVENTION

It is therefore one of the objects of the present invention to obviatethe disadvantages of prior art diaphragms and to provide ahydraulically-operated diaphragm valve which has a long operating lifeand can be closed reliably even when the valve has been left open for anextended period.

It is a further object of the present invention to provide a valvediaphragm which can be manufactured at a moderate cost.

In particular it is an object of the present invention to provide adiaphragm which can be operated when fitted into a hydraulicallyoperated valve without the use of a metallic spring.

Yet a further object of the invention is to provide a diaphragm suitablefor use in 8″ and larger valves.

SUMMARY OF THE INVENTION

The present invention achieves the above objects by providing anelastomer diaphragm for use in a hydraulically-operated valve and in ahydraulic pressure regulator, said diaphragm being provided with anupper face arranged to be exposed to a control hydraulic pressure and alower face arranged to selectively seal and open a passage between avalve inlet and a valve outlet, ribs on said upper face urging saiddiaphragm towards a sealing position, said diaphragm being characterizedby the addition of an elastomer ring element disposed adjacent to saidupper face and adjacent to the largest diameter of the diaphragm exposedinside a valve to which it may be assembled, an upper face of saidflexible ring element being in pressure contact with a portion of the srigid body of said valve, said flexible ring element further urging saiddiaphragm towards its lower position and allowing closure of said valvewithout use of a metallic compression spring.

In a preferred embodiment of the present invention there is provided anelastomer diaphragm, wherein said flexible ring element and saiddiaphragm are separate components.

In a most preferred embodiment of the present invention there isprovided a 200 mm or larger hydraulically-operated valve fitted with adiaphragm as described.

It will thus be realized that the novel diaphragm of the presentinvention serves to allow valve closure by means of the flexible ring incombination with the ribs molded on the upper face of the diaphragm. Thedimensions and number of ribs are determined by the diameter of theattached pipeline.

Several features of previously-developed improvements, such as ribformation and a textile center reinforcing element, are also retained inthe diaphragm of the present invention. However the addition of anelastomer ring element disposed adjacent to and pressing on the upperface of the diaphragm is the innovation central to the presentinvention. It has been found that the downward pressure applied adjacentto the largest free diameter is most helpful for closing the valve yetdoes not substantially increase force needed to open the sealed passagefor fluid flow. A likely explanation for this surprising situation isthat movement for the closure (downward) action starts at the outersection of the diaphragm, with assistance from the ring element, whereasthe opening of the diaphragm proceeds first from the center and movesonly later towards the outer diameter.

Costs can be reduced by use of a commercially-available ‘O’ ring orshaft seal to serve as an elastomer ring element. Such rings and sealsare available as standard items in diameters of up to 1 meter or morefrom manufacturers such as Martin Merkel, Hamburg, and others.

While the 2-way valves shown in the figures are used in largerquantities than pressure regulators, not shown, which have manysimilarities to valves, the operational requirements of the pressureregulators are more severe due to more frequent operation. Theimportance of a long-life diaphragm for regulators is therefore of greatimportance.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will now be described further with reference to theaccompanying drawings, which represent by example preferred embodimentsof the invention. Structural details are shown only as far as necessaryfor a fundamental understanding thereof The described examples, togetherwith the drawings, will make apparent to those skilled in the art howfurther forms of the invention may be realized.

In the drawings:

FIG. 1 is a cross-sectional elevational view of a preferred embodimentof the diaphragm according to the invention;

FIG. 2 is a plan view of the same;

FIG. 3 is a plan view of the same diaphragm turned downside up;

FIG. 4 is a sectional view of a first embodiment of the flexible ringelement;

FIG. 5 is a sectional view of a second embodiment of the flexible ringelement;

FIG. 6 is a sectional view of a third embodiment of the flexible ringelement;

FIG. 7 is a sectional elevational view of a closed 2-wayhydraulically-operated valve using the diaphragm according to theinvention; and

FIG. 8 is a sectional elevational view of the same valve shown in itsopen position.

FULL DESCRIPTION OF THE INVENTION

There is seen in FIGS. 1, 2 and 3 an elastomer diaphragm 10 for use in ahydraulically-operated valve (seen in FIG. 7) and in a hydraulicpressure regulator (not shown).

The material to be used for manufacturing the diaphragm is dependent onthe type of fluid being carried and on the temperature range to whichthe diaphragm is to be exposed. Typical suitable materials are Nitrilebutadiene rubber and Neoprene. The diaphragm 10 has an outer,substantially flat area 12 allowing clamping by the valve (seen in FIG.2) an orientation tab 13 and multiple apertures 14 for passage offasteners (not seen). Area 12 is provided with sealing beads 16, asknown in the prior art. (U.S. Pat. No. 2,302,930 to Anderson)

The central portion 18 of the diaphragm 10 is bulged to avoid excessivestretching of the diaphragm material when in use, and to enhancestability in both upper and lower positions.

An upper face 20 is arranged to be exposed to a control hydraulicpressure. Tangential ribs 22 and radial ribs 23 on the upper face 20urge the diaphragm 10 downwards towards a lower sealing position, seenin FIG. 7. Additionally the diaphragm comprises an elastomer ringelement 24 disposed adjacent to the upper face 20 and adjacent to thelargest diameter of the diaphragm exposed inside a valve to which it maybe assembled. When assembled an upper face of the flexible ring element24 is in pressure contact with a portion of the rigid body of the valve.Thus the flexible ring element 24 assists in urging the diaphragmtowards its lower position and allowing closure of the valve, as seen inFIG. 8.

In the present embodiment the flexible ring element 24 is produced aspart of an integral diaphragm molding.

The lower face 26 of the diaphragm 10 is arranged to selectively sealand open a passage between a valve inlet and a valve outlet, whenassembled as in FIG. 7. A central projection 28 on the lower face 26 isused for sealing. Two further projecting ridges 30, parallel to thecenter line, reduce vibration and thus act as noise suppressers. A pairof support pads 32 are shown which contact a rib of the valve casingwhen in the lower sealing position, as seen in FIG.7. In practice onlyof the two ridges 3 0 or pads 32 are active while the second beingpassive depending on the direction of flow.

A reinforcing central layer 34 is molded in between the upper 20 andlower face 26. The layer 34 is freely flexible, but resistant to tensileforces. Suitable materials for layer 34 include cotton and nylon.

With reference to the rest of the figures, similar reference numeralshave been used to identify similar parts.

Seen in FIG. 4 is a flexible ring element 36 which has a circularcross-section. The flexible ring element 36 and the remainder of thediaphragm are separate components. This simplifies the molding dierequired for production of the diaphragm and also opens the possibilityof selecting a material for the ring different from the material usedfor the main body of the diaphragm.

A further advantage of this design is the wide availability of ‘O’ ringsand the moderate cost thereof.

Referring now to FIG. 5, there is depicted a flexible ring element 38which has a trapezoidal cross-section. A small relief area 40 at themidpoint of the longest side 42 extends the compression range of thering element 38.

FIG. 6 shows a flexible ring element 44 which has a V-shapedcross-section 46. This form has a long pressure range. The tapered wings48 of the V prevent stress-concentration damage to the diaphragm whenpressed thereagainst.

FIGS. 7 and 8 illustrate a hydraulically-operated valve 50 fitted with adiaphragm 10. Inlet port 52 and outlet port 54 diameter exceeds 8″ (ormay be less). The diaphragm, as described with reference to FIG. 1, isoperated without use of a metallic compression spring. The valve isshown in the closed position in FIG. 7 and in the open position inFIG.8.

A three-way valve 56 is in fluid communication with the upper chamber58. A tube 60, seen in FIG. 8, connects the inlet port 52 to port A ofthe three-way valve 56, so that the hydraulically-operated valve 50closes because hydraulic pressure is equalized on both faces of thediaphragm 10, and the flexible ring element 24 together with the ribs 22urge the diaphragm 10 downwards.

To reopen the valve 50 hydraulic pressure in the upper chamber 58 isreduced by releasing the liquid contents thereof through port B.

If the fluid being handled is water, and the occasional spillage of asmall quantity of fluid is acceptable, there is no need to connect thethree-way valve 56 to the outlet port 54, as the upper chamber 58 can bevoided to the ground through port B of the three-way valve 56, as seenin FIG. 7.

The scope of the described invention is intended to include allembodiments coming within the meaning of the following claims. Theforegoing examples illustrate useful forms of the invention, but are notto be considered as limiting its scope, as those skilled in the art willreadily be aware that additional variants and modifications of theinvention can be formulated without departing from the meaning of thefollowing claims.

1. An elastomer diaphragm for use in a hydraulically-operated valve andin a hydraulic pressure regulator, said diaphragm being provided with anupper face arranged to be exposed to a control hydraulic pressure and alower face arranged to seal and open a passage between a valve inlet anda valve outlet, ribs on said upper face urging said diaphragm towards asealing position, said diaphragm being characterized by the addition ofan elastomer ring element disposed adjacent to said upper face andadjacent to the largest diameter of the diaphragm exposed inside a valveto which it may be assembled, an upper face of said flexible ringelement being in pressure contact with a portion of the rigid body ofsaid valve, said flexible ring element further urging said diaphragmtowards its lower position and allowing closure of said valve withoutuse of a metallic compression spring.
 2. The elastomer diaphragm asclaimed in claim 1, wherein said flexible ring element has a circularcross-section.
 3. The elastomer diaphragm as claimed in claim 1, whereinsaid flexible ring element has a trapezoidal cross-section.
 4. Theelastomer diaphragm as claimed in claim 1, wherein said flexible ringelement has a V-shaped cross-section.
 5. The elastomer diaphragm asclaimed in claim 1, wherein said flexible ring element and saiddiaphragm are separate components.
 6. The elastomer diaphragm as claimedin claim 1, wherein said flexible ring element is produced as part of anintegral diaphragm molding.
 7. A hydraulically-operated valve fittedwith a diaphragm as claimed in claim 1.